The telephone is a powerful and pervasive communications tool that unfortunately permits strangers to intrude into our home by simply dialing our telephone number. Nearly everyone has received undesirable telephone calls from telemarketers, "wrong number" type callers, obscene or harassment-type callers, and other undesirable callers (e.g., telephone "friends" who talk for such long time periods that personal visits would be more practical). We often wish there was some way to automatically screen such undesirable calls and allow us to answer the telephone only when a person we wish to talk to is on the other end of the telephone line. It sometimes seems the only practical way for most residential telephone users to evade such calls is to permit all incoming calls to ring unanswered. Most people, however, refuse to resort to this drastic measure because it forces desired incoming calls to also be ignored.
One commonly used technique to evade undesired incoming calls is to connect an automatic telephone answering machine to the telephone line. The answering machine automatically answers all incoming calls and repeats a prerecorded message and a message left by the caller over a speaker--permitting the person called to screen the call and pick up the telephone if he wishes to talk to the caller. Unfortunately, many callers simply refuse to "talk to" answering machines, and may therefore hang up without providing the person called with an opportunity to decide whether or not he wishes to answer the call.
It is generally known to automatically screen telephone calls by providing apparatus which (a) automatically "answers" an incoming call, (b) requires the caller to key in one or more TOUCH TONE digits, (c) disconnects the caller if the digits do not match predetermined digits, and (d) sound an audible alarm if the digits keyed in by the caller match the predetermined digits. See, for example, the following prior issued patents which relate to such prior art call screening systems:
U.S. Pat. No. 4,387,272 to Castro et al.
U.S. Pat. No. 3,936,617 to Bolgiano
U.S. Pat. No. 3,902,016 to Blouch
U.S. Pat. No. 4,611,098 to Giorgio et al.
U.S. Pat. No. 4,074,078 to Jansen
U.S. Pat. No. 4,446,334 to Groff
U.S. Pat. No. 4,369,339 to Castro et al.
U.S. Pat. No. 4,639,552 to Hall
U.S. Pat. No. 4,383,138 to Castro et al.
U.S. Pat. No. 4,393,278 to Miyoshi
U.S. Pat. No. 3,654,396 to Biezeveld
U.S. Pat. No. 4,453,041 to Castro et al.
U.S Pat. No. 4,488,005 to Frantz
U.S. Pat. No. 4,006,316 to Bolgiano
However, further improvements are possible. For example, while such prior systems in some cases provide adequate call screening capability, they generally suffer from the disadvantages of being too complicated and expensive and provide only limited additional PBX type functions (e.g., intercom capability, hold capability, programmable call screening). In addition, inexpensive existing systems often require an external alarm type device to notify the subscriber that a properly screened call is coming in (rather than using the existing telephone ringer), and are incapable of powering telephones.
My invention, in contrast, provides an inexpensive and relatively uncomplicated telephone answering device which provides call screening and additional advanced functions not typically provided in home telephone systems. Through use of my invention, a homeowner or small businessman can obtain, at low cost, many of the features and functions of more complex and expensive telephone systems.
My invention provides, for example, a telephone answering device that is capable of not only screening out undesirable calls, but also of screening the calls that are dialed out, adding the "hold" function to all telephones (activated by depressing a TOUCH TONE key on a standard telephone set), and providing a way to use the telephones in the home as an intercom system. The present invention is fully compatible with an answering machine, which can be used to record either all incoming calls or record only screened incoming calls. No other satisfactory system of relatively nominal expense exists which can provide all of these fully programmable functions.
The following is a list of some of the significant advantageous features provided by the preferred embodiment of the present invention:
Inexpensive, compact and reliable;
Telephones are powered so that electronic telephones retain their memories and other advantages are obtained;
Fully programmable through a standard TOUCH-TONE telephone set;
A user programmable entrance code prevents unauthorized users from reprogramming the system;
Both incoming and outgoing call screening can be provided;
Multiple call screening codes can be accepted and maintained;
Different ringing cadences can be provided to distinguish between different call screening codes;
Ringer cadences can be easily changed:
Hold function is provided using standard residential type telephone equipment;
Home intercom capability uses existing standard telephone sets;
Failsafe feature automatically connects telephone sets directly to telephone company lines so a local power failure does not cause telephone service to be lost;
System uses standard Bell hook status and ringer voltages and currents (AC and DC);
Five Ringer Equivalence Numbers (R.E.N.s) are provided, thus permitting up to five telephone sets or equivalents (this is the same maximum number guaranteed by most telephone companies);
Any feature of the system can be used in combination with any other feature;
Dial screening can prevent certain preprogrammed numbers from being dialed out; and
A simulated call transfer function permits the user to place an incoming call on hold and then again ring of all the extensions to request someone else to take the call.